Wear your dragon-hide gloves; it can do funny things to the skin when undiluted, bubotuber pus."
-- Professor Sprout (GF13)
The stinky pus of a magical bubotuber plant, used diluted as a cure for acne. Undiluted it can burn the skin, and smells strongly of petrol (GF13).
The pimple-curing properties were discovered by Sacharissa Tugwood (FW), which was mentioned on the First Wombat Test (JKR -W1).
Bubotuber pus is a good alternative for students like Eloise Midgen, who tried to curse away her acne and managed to remove her nose (Madam Pomfrey put it back) (GF13).
When Rita Skeeter wrote about a supposed teenage love-triangle between Harry, Hermione and Viktor Krum, someone sent Hermione an envelope full of bubotuber pus to express their outrage. When she opened it, her hands swelled up (GF14).
Bubotuber pus is used in healing potions for the skin.
From the Medieval Latin būbō for "swelling pustule," and "tuber" meaning "fleshy root" from Latin "tumere" = "to swell"
bubo = (Gr. boubôn, "groin") (plural form: buboes) is a swelling of the lymph nodes. It is found in infections such as bubonic plague. It is similar in appearance to a huge blister, and usually appears under the armpit, in the groin or on the neck. Tuber = In anatomy, the term tubercle may describe a round lump or warty outgrowth found on bones or skin, or, in cases of tuberculosis, in the lungs (Wikipedia).